Plate clamp for printing machines



New. M, W39.

ou ao/ao ooll- G. M. KELLER ET AL PLATE CLAMP FOR PRINTING MACHINESFiled Aug. 2l, 1937 4 Sheets-Sheet l 7L L@ 25;@ M15;

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Filed ug- 21, 1937 L A R E L L E K M G PLATE CLAMP FOR PRINTING MACHINESM 31939- G. M KELLER Er AL.

PLATE CLAMP FOR PRINTING MACHINES Filed Aug. 2l, 1937 ENTORS )CQ/guySheets-Sheet 3 f Il f V f m v f Nov; M, 1939. G. M. KELLER ET A1.

PLATE CLAMP FOR PRINTING MACHINES Filed Aug. 2l, 1937 4 Sheets-Sheet 4Mic/ INVENTQRS.

Patented Nov. 14, 1939 UNITED STATES PATENT OFFICE PLATE CLAMP FonGeorge M, Keller, Rochester,

Huck, Richmond Hill, N. Y.,

PRINTING MACHINES and William F. assignors to R.

Hoe & Co., Inc., New York, N. Y., a corpora- This invention relates toplate clamping means for printing and like machines, and moreparticularly to a plate clamping mechanism which includes a margin bar,arranged for use in securely clamping the straight edge of a curvedprinting plate to a form cylinder of a printing machine.

The plate clamping means of this invention is particularly adapted andarranged to engage the straight edge of a curved plate upon a formcylinder of a printing machine and hold it tightly thereagainst toprevent this plate edge from bowing upwardly away from the cylinder, dueto centrifugal force developed when the cylinder is rotated or othercause. The clamping means of this invention includes a margin bararranged on the cylinder to engage the straight edge of a curvedprinting plate, and means associated with this bar and actuated bycentrifugal force developed by the rotative movement of the cylinder, tocause this bar to press against, and clamp, the plate to the cylinder bya pressure, which increases in proportion to the speed of rotation ofthe cylinder.

One object of this invention is to provide an improved plate clampingmeans of the above nature.

Another object is to provide in combination with a curved platereceiving cylinder, means actuated by centrifugal force developed whenthe cylinder is rotated, to securely hold a straight edge of the curvedplate against the cylinder.

It is also an object of this invention to provide a plate clamping meansof generally improved construction, whereby the device will be simple,durable and inexpensive in construction, as well as convenient,practical, serviceable and efficient in its use.

With the foregoing and other objects in view, which will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts, and in the details of construction hereinafterdescribed and claimed.

The preferred embodiment of this invention is illustrated in theaccompanying drawings, where- Figure l is a face view of a form cylinderof a printing machine, with plate clamping means embodying the featuresand principles of this invention associated therewith;

Figure 2 is an enlarged plan View of one end of a pair of printingplates and the margin bar constituting a part of the clamping means ofthis invention disposed between the straight edges thereof;

1937, Serial No. 160,218

(Cl. lOl- 378) Figure 3 is a longitudinal section taken on line 3-3 ofFigure 2;

Figure 4 is a cross sectional view taken on line 4-4 of Figure 2 andshowing the position of the parts when the cylinder is rapidly rotating;

Figure 5 is a cross sectional view similar to Figure 4 but showing theposition of the parts when the cylinder is not rotating;

Figure 6 is a sectional view taken on line 6-6 of Figure 5;

Figure '7 is an enlarged plan view of one end of a pair of printingplates and a somewhat modifled form of margin bar constituting a part ofthe clamping means disposed between the straight edges thereof;

Figure 8 is a cross sectional view taken on line 8-8 of Figure 7;

Figure 9 is an enlarged plan view of another modified form of margin bardisposed between the straight edges of a pair of printing plates;

Figure 10 is a cross sectional View taken-on line Ill- Ill of Figure 9;

Figure 11 is an enlarged plan view of another modified form;

Figure 12 is a sectional view taken on line I2-I2 of Figure 11;

Figure 13 is an enlarged plan view of still another modiiied form; and

Figure 14 is a sectional view taken on line ll-fil of Figure 13.

The features and principles of this invention being especially adaptedfor association with the form cylinder of a printing machine, thedrawings illustrate a form cylinder II having shaft ends I2 and I3extending from its ends whereby it may be journaled in suitable supports(not shown) and be rotated to perform its usual function in combinationwith the other mechanisms of a printing machine. The cylinder Il isadapted to have a plurality of curved printing plates I4 mounted thereonand is provided with the usual curved edge clamping and locating membersI5 and straight edge locating blocks I6. The plates Il generally extendperipherally about the cylinder I I and have the straight edges I1 and I8 of one plate slightly spaced from, and in opposed relation to, thestraight edges I1 and IB of another plate, the opposing edges of bothplates being in abutment-with the edgel locating blocks I6.

The clamping members I5 impose a cross pressure upon the plates I4 andthe rapid rotation of the cylinder II develops centrifugal force, bothof which forces tend to bulge the centerof the plate I4 away from thecylinder. This bulging tendency is greatest at the straight edges I1 andI8 of the plates I4 for the central portions I8 are inherently stiifenedby their arcuate formation. 'Ihis invention provides means to counteractthis bulging tendency by the provision of margin bars 2I and 22, eachhaving a shoulder 23 adapted to overlie a corresponding shoulder 24formed on the straight edges I1 and I8 of the plate I4. Herein themargin bars 2| and 22 are shown provided with oppositely directedshoulders 23 whereby the shoulders 24 on the opposed edges I 1 and I8 ofadjacent plates I4 will be simultaneously engaged.

The margin bars 2| and 22 extend lengthwise of the cylinder II along thestraight edges I1 and I8 of the plates I4 and are each secured to acylindrical weight 25, by means of a plurality of tie rods 28 whichfreely pass through openings 21 formed in the cylinder II. Each of theweights 25 is preferably disposed in an opening 28 formed in, andextending lengthwise of, the cylinder II and which is preferablydisposed adjacent the periphery of the cylinder II and diametricallyopposite the margin bar connected thereto. The openings 21 arepreferably radially directed through the cylinder and are slightlylarger in diameter than the rods 28 to permit a small amount of freemovement for the margin bar in any direction. Likewise, the openings 28are larger in diameter than the weights 25 to permit transverse movementof the weights therein. The bars 2| and 22 are connected to the rods 26by screws 29 and the weights 25 are connected to the rods 26 by screws3l.

Herein the weights 25 are shown somewhat longer than the margin bars 2|and 22, and these bars are shown somewhat shorter than a groove 32provided in the cylinder I I to receive them. The margin bars 2l and 22in this instance are T shaped in cross-section, the body portion beingdisposed in the groove 32 and the arm portions forming the oppositelydirected shoulders 23.

'I'he groove 32 in which one of the bars 2| and 22 is disposed, is shownin communication with the openings in which the weight 25, connected tothe opposite margin bar, is disposed. The tie rods 25 connecting one barwith its associated weight are shown passing through openings 33, formedin the weight connected with the opposite bar.

Each weight 25 is counterbored as at 34 to receive a compression spring35. 'I'he counter-l bores 34 are herein shown in alignment with the tierods 26, connected to the respective weight, and the spring 35 istherefore arranged to encircle the head of the screw 8| which isdisposed in the counterbore. The springs 35 react between the bottom ofthe counterbores 34 and the undersurface of the margin bar overlying therespective weight which is connected to the opposite margin bar, wherebythe bars 2| and 22 with their associated parts, tie rods 28 and weights25 may be referred to as being floatingly mounted in the cylinder II. Itwill be obvious that, if margin bars are not diametrically opposed, thesprings 35 can be arranged to react between the bottoms of thecounterbores 34 and any suitable abutment secured to or forming part ofthe peripheral wall 36 of the cylinder II, and overlying the weightopenings 28. Y

In thearrangement shown, the springs 35 in one weight 25 reactingagainst the margin bar connected to the opposite weight tends t0 reatean equalizlng effect whereby the action of the opposite margin bars 2land 22 will engage the respective plate edges I1 and I8 withsubstantially equal pressure. Preferably the springs 85 are tensionedonly sumciently to counterbalance the weight of the parts associatedtherewith and not sufllciently to interfere with the movements of theseparts to press the margin bar upon the plate edge to clamp the straightplate edge to the cylinder II.

'Ihe margin bars 2| and 22 are forced against the straight plate edgesI1 and I8 due to centrifugal force developed by rotation of the cylinderIl and acting on the weights 25 to throw them outwardly.' Movement ofthe weights transversely in the openings 28 will, through the tie rods28, press the margin bar shoulders 23 against the correspondingshoulders 24 on the opposed straight edges I'I and I8 of the plates I4,to clamp these edges tightly to the cylinder II. Obviously, the fasterthe cylinder II rotates the .more centrifugal force is developed andhence the pressure of the margin bars 2I and 22 upon the plate straightedges will be correspondingly increased, thus overbalancing the tendencyfor these edges to bulge as above described, and maintaining themtightly against the periphery of the cylinder II.

In the form shown in Figures 7 and 8, the margin bar, disposed betweenthe opposing straight edges I1 and I8 of the plates I4, is constitutedby members 4I' and 42, each having a flange 43 extending along its outeredge to provide oppositely directed shoulders 44 adapted to overlie thecorresponding shoulders 45 formed on the straight edges I 1 and I8.'I'he abutting surfaces between the shoulders 44 and 45 are inclinedfrom 4the plate edges I 'I and I8 outwardly toward the periphery wherebywhen the members 4I and 42 are spread apart the plates I4, at theiredges I1 and I8, will be more firmly pressed against the cylinder II.

'Ihe means to spread the members 4I and 42 apart includes a weight 48disposed in a longitudinally extending opening 41 formed in the cylinderII adjacent its periphery and directly below the plate straight edges I1 and I8. The weights 46 are normally pressed radially outwardly bysprings 48 and are guided in any radial movements by studs 49 whichextend through the weights and into the cylinder II from a memberspreading bar 5I. Each bar 5I has a base 52 seated in a groove 53 formedin the respective weight 46 and extends radially outwardly therefrombetween the members 4I and 42. Adjacent the weight 46 the side surfacesof the bar 5I are inclined toward each other as at 54 from the base 52to an intermediate straight portion 55, the side surfaces of which areparallel, and then the side surfaces are again inclined toward eachother as at 56.

Intermediate the inclined side surfaced portions 54 and 56 of the bar 5Iand the adjacent members 4I and 42 non-friction members 51, such ashardened steel rods, may be disposed in recesses 58 formed in themembers 4I and 42 against which these inclined surfaces act to spreadthe members 4I and 42, when centrifugal forge urges the weights 46outwardly. The spreading action of the members 4I and 42 tends to forcethe inclined surfaces 44 of the members 4I and 42, peripherally over theinclined surfaces 45 of the plate edges I1 and I8 respectively, andincreasing centrifugal force developed by increasing speed of rotationof the cylinder II will increasingly clamp the plate edges I1 and I8against the cylinder. l

In the form shown inFlgures 9 and 10, the margin bar disposed betweenthe opposing straight edges I1 and I8 of the plates I4 is constituted bya pair of cooperating members 6| and 62, each having a flange 63extending along its outer edge to provide oppositely directed shoulders64 adapted to overlie corresponding shoulders -05 formed on the straightedges I1 and I8. As in the previously described form, the abuttingsurfaces between the shoulders 64 and 65 are inclined so that when theflanges 63 of the members BI and 62 are spread apart these edges will bemore rmly pressed against the cylinder II.

lI'he members 6| and 62 extend from the flanges 63 into the cylinder IIthrough a slot 66, and have their inner edges fulcrumed respectively onthe opposing inner edge 60 of the slot 66 where it joins an opening 61extending longitudinally through the cylinder II adjacent its peripheryand directly beneath the plate edges I1 and I8. Each of the members 6Iand 62 is provided with a finger-like extension or extensions 68, theends 69 of which are adapted to seat upon a flattened area 1| formed ona weight 12 disposed in the openings 61. A curved fulcrum surface 'I3 isprovided between and on each of the members 8| and 82 whereby when thefingers 68 are spread by the action of the weight 12 being urgedoutwardly by centrifugal force the flanges 03 will be spread apart.Springs 14 are provided to react between the surface of the openings 61and the weights 12 to constantly maintain the parts in engagement.

In the form shown in Figures l1 and l2, the margin bar is constituted bya plurality of members 8I and 82, each having a flange 83 extendingalong its outer edge forming a shoulder 84. The members are disposed injuxtaposed position with the flanges 83 oppositely directed whereby theshoulder 84 of one will overlie the straight edge I1 of one plate andthe shoulder 84 of the next adjacent one will overlie the straight edgeI8 of the other plate. The members 8| and 82 extend into the cylinder IIand are each secured to a curved plate 85 disposed in a longitudinallyextending opening 86 through a slot 81.

An edge 88 of each of the plates 85 is adapted to seat upon one of aseries of shoulders 89 alternately formed on the sides of a weight 9|disposed in length to extend under all of the members 8| and 82. Theother edge 92 of each of the plates 85 overlies a hole 93 formed in theside of the weight 9| opposite each of the shoulders 89 and is engagedby a spring 94 seated in the hole 93.

When the cylinder II is rotating rapidly, the parts assume the positionsshown in Figures 11 and 12, the weight 9| being urged outwardly towardthe periphery of the cylinder by centrifugal force. Movement of theweight 9| toward the periphery of the cylinder I has moved the curvedplates 85 within the opening 86 against the tension of the springs 94and the shoulders 84 of the flanges 83 have engaged the respectiveprinting plate edges I1 or I8 to securely clamp the plates to thesurface of the cylinder II. When the cylinder cornes to rest, thesprings 94 will reversely move the curved plates 85 to release theclamping engagement of the shoulders 04 of the flanges 83 with the plateedges I1 and I8.

Referring to the form shown in Figures 13 and 14, members 96 and 91extend through a slot the opening 86 and which is of suilicient 98formed in the cylinder II from a sleeve member 99 disposed in alongitudinally extending opening |0| formed in the cylinder II.v Eachmember 96 and 91 is provided with a flange |02 forming a shoulder |03which is adapted to overlie the adjacent straight edges Il'and I8respectively of the printing plates. The members 96 and 91 are arrangedin juxtaposed position inl the cylnder and have their flanges |02alternately directed to engage opposing printing plate edges.

A weight |04 extends through all of the sleeve members 99 and isconnected to each member by a lug |05 extending inwardly from theinternal periphery of the members 99 into a slot |08 provided in theweight. The lugs |05 of the members 99 are disposed on the side of themember opposite to that side toward which the flanges |02 extend and themembers 99 are assembled on the weight |04 "'ith the lugs |05 ofadjacent members alternately directed, whereby movement of the weight|04 outwardly under the urge of centrifugal force when the cylinder |Iis rotated will cause the alternate sleeve members 99 to oppositelytwist and the flanges |02 on the respective members 96 and 91 willtherefore clampingly engage the printing plate edges I1 and I8respectively as shown in Figures 13 and 14. Springs |01 disposed inholes |08 formed in the weight |04 will react between the weight andeach of the sleeve members 99 to twist the latter back into their normalposition when the cylinder stops rotating.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or essential attributesthereof, and it is therefore desired that the present embodiment beconsidered in all respects as illustrative and not restrictive, and itwill be further understood'that each and every novel feature andcombination present in or possessed by the means herein disclosed formsa part of the invention included in this application.

What we claimis:

l. In plate clamping mechanism for the form cylinder of a printingmachine adapted to use pre-curved printing plates, a margin bar arrangedto operably move radially with respect to the axis of the cylinder, toengage a straight edge of a plate and clamp it to the cylinder, and aweight connected to the margin bar whereby it is moved to clamp theplate when the machine is operated.

2. In plate clamping mechanism for the form cylinder of a printingmachine adapted to use curved printing plates, a movable margin bar, andmeans actuated by centrifugal force to operably move said bar intoengagement with an edge of a plate on the cylinder and clamp it to thecylinder.

3. In mechanism for clamping a curved plate to the form cylinder of aprinting machine, a movable margin bar extending lengthwise along andover a straight edge of the plate, and centrifugally affected means to.move said bar into clamping engagement with the plate straight edge tosecure it to the cylinder.

4. In mechanism for clamping a curved plate to the form cylinder of aprinting machine, a margin bar extending along and over an edge of -theplate, and means actuated by centrifugal force developed by the rotationof said cylinder to cause said bar to engage and clamp the plate to thecylinder by pressure varying with the rotative speed of said cylinder.

5. In a printing plate clamping mechanism, a

margin bar adapted to extend along and over an edge of the plate andbeing arranged to be operably moved into engagement with the plate edgeand to clamp it to a cylinder of a printing ma- 5 chine, means actuatedby centrifugal force developed by the rotation of the cylinder to somove the bar, and means to move said bar out of engagement with saidedge.

6. In a printing plate clamping mechanism, a

margin bar adapted to extend along and over an edge of the plate andmounted adjacent the plate edge to be operably moved into engagementwith the plate edge and to clamp it to a cylinder of a printing machine,and a weight connected to said bar and actuated by centrifugal i'orce toso move said margin bar.

7. In a printing plate clamping mechanism, a rotatable cylinder, amargin bar arranged to overlie a straight edge of a printing plate onsaid cylinder, and a weight carried by said cylinder to be acted upon bycentrifugal force developed by the rotative movement of said cylinder tomove said bar into engagement with the edge of said printing plate andclamp it to said cylinder.

8. In a printing plate clamping mechanism for securing printing platesto a rotatable form cylinder of a printing machine, a margin bar adaptedto overlie a straight edge of the printing plate, and a weight connectedto said bar and movable by centrifugal force to cause said bar to clampthe plate edge to the cylinder.

9. In a clamping mechanism for securing printing plates to a rotatableform cylinder of a printing machine, a movable margin bar adapted tooverlie an edge of the printing plate, and a weight operably connectedto said bar and carried by said cylinder to be affected by centrifugalforce due to the rotative movement of the cylinder to cause said bar toclamp the plate to the cylinder.

10. In a mechanism for securing a curved plate upon a rotatable formcylinder of a printing machine, a margin bar mounted on the cylinder tooverlie and moved toward an edge of the plate, and a radially movableweight carried by the cylinder and connected to said bar to move the barinto clamping engagement with the plate edge when the cylinder isrotated.

1l. In a plate clamping mechanism for securing a curved plate upon arotatable form cylinder of a printing machine, a margin bar mounted onthe cylinder to overlie and move toward an dge of the plate, a weightcarried by the cylinder and connected to said bar to move the bar intoclamping engagement with the plate edge when the cylinder is rotated,and resilient means to release the bar from clamping engagement with theplate edge when the cylinder is at rest.

12. In a plate clamping mechanism for securing curved plates upon arotatable form cylinder of a printing machine, an inwardly movablemargin bar disposed between opposing plate edges and being adapted tooverlie each edge, a weight carried by the cylinder and arranged to move14. In a plate clamping mechanism for secur- A ing a pair ofsubstantially semi-cylindrical curved plates to a rotatable formcylinder of a printing machine, movable margin bars carried by thecylinder adjacent to and overlying adjacent straight edges of theplates, a centrifugally movable weight connected to each bar and beingdisposed adjacent the other bar, whereby centrifugal force developed bythe rotation of said cylinder will cause said bars to engage therespective plate edges adjacent thereto.

15. In a plate clamping mechanism for securing a pair of substantiallysemi-cylindrical plates to a rotatable form cylinder of a printingmachine, movable margin bars carried by the cylinder adjacent to andoverlying opposite straight edges of the plates, centrifugally movableweights carried by the cylinder each connected to one bar and disposedadjacent the other bar, whereby centrifugal force developed by therotation of said cylinder will cause said bars to engage the plate edgesadjacent thereto, and a spring acting against each weight to hold saidbars out of engagement with the plate edges, when the cylinder is atrest.

16. In mechanism to clamp a plate to a cylinder, a margin bar adapted toextend along and over an edge of the plate and being arranged to bemoved radially with respect to the cylinder into engagement with theplate edge to clamp it to the cylinder, and means actuated bycentrifugal force developed by the rotation of the cylinder to so movethe bar.

1'7. In mechanism to clampfaiplate to a cylinder, a margin bar adaptedto extend along and over an edge of the plate and being arranged to bemoved peripherally with respect to the cylinder into engagement with theplate edge to clamp it to the cylinder, and means actuated bycentrifugal force developed by rotation of the cylinder to so move thebar.

18. In mechanism to clamp the opposing edges of plates to a cylinder, amember adapted to extend along and over each edge and being arranged tobe moved peripherally with respect to the cylinder into engagement withthe respective plate edge to clamp it to the cylinder, and meansactuated by centrifugal force developed by the rotation of the cylinderto simultaneously move said members.

GEORGE M. KELLER.

WILLIAM F. HUCK.

